There presently exists a population of over 4 billion people that are generally dissatisfied and underserved by the poor sound quality of short-wave radio broadcasts, or the coverage limitations of amplitude modulation (AM) band and frequency modulation (FM) band terrestrial radio broadcast systems. This population is primarily located in Africa, Central and South America, and Asia. A need therefore exists for a satellite-based direct radio broadcast system to transmit signals such as audio, data and images to low-cost consumer receivers.
A number of satellite communications networks have been developed for commercial and military applications. These satellite communications systems, however, have not addressed the need to provide multiple, independent broadcast service providers with flexible and economical access to a space segment, nor consumers' need to receive high quality radio signals using low-cost consumer radio receiver units. A need therefore exists for providing service providers with direct access to a satellite and choices as to the amount of space segment that's purchased and used. In addition, a need exists for a low-cost radio receiver unit capable of receiving time division multiplexed downlink bit stream.